java小白——UDP服务器客户端传输数据

ゝ一世哀愁。 2023-06-19 06:49 9阅读 0赞

UDP属于无连接的传输协议  
因此传输数据时应创建一个数据发送包，一个数据接收包。在java实现如下  
**服务器**

package 网络编程;
    
    import java.net.DatagramPacket;
    import java.net.DatagramSocket;
    import java.net.InetAddress;
    import java.net.SocketException;
    
    public class ServerTestUDP {
        
    
    	public static void main(String[] args) {
        
    		DatagramSocket socket = null;//设置服务器的套接字
    		DatagramPacket server_send = null;//设置发送包
    		DatagramPacket server_recive = null;//设置接收包
    		int port = 5151;//
    		try {
        
    			socket = new DatagramSocket(port);//实例化服务器套接字
    			System.out.println("服务器启动");
    			byte []r = new byte[1024];//建立一个缓冲流对象
    			server_recive = new DatagramPacket(r, r.length);//建立接收包对象
    			socket.receive(server_recive);//得到接收包
    			InetAddress address = server_recive.getAddress();//从接收的包中获取ip地址
    			int clientport = server_recive.getPort();//获取端口号
    			byte []data = server_recive.getData();//获取数据
    			int len = server_recive.getLength();//获取数据包长度
    			String str = new String(data,0,len);//将接收包转换为字符串
    			System.out.println("客户端ip地址:"+address);//输出
    			System.out.println("客户端端口号:"+port);//
    			System.out.println("客户端信息："+str);//
    			String str1 = "hello,我是server！";
    			byte []s = str1.getBytes();//为发送的字符串设立一个缓冲流存储它
    			server_send = new DatagramPacket(s, s.length,address,clientport);//实例化发送包的对象
    			socket.send(server_send);//发送发送包
    			
    			
    		} catch (Exception e) {
        
    			
    			e.printStackTrace();
    		}finally {
        
    			socket.close();
    		}
    
    	}
    
    }

**客户端：**

package 网络编程;
    
    import java.net.DatagramPacket;
    import java.net.DatagramSocket;
    import java.net.InetAddress;
    
    public class ClientTestUDP {
        
    
    	public static void main(String[] args) {
        
    		DatagramSocket socket = null;//设置客户端的UDP连接的套接字
    		DatagramPacket packet_send = null;//设置发送包对象
    		DatagramPacket packet_recive = null;//设置接收包对象
    		String server = "127.0.0.1";//设置服务器的地址
    		int port = 5151;//服务器的端口号
    		String str = "我是clientA";//向服务器发送的信息
    		byte[] data = str.getBytes();//建立缓存流向data里输入信息
    		try {
        
    			socket = new DatagramSocket();//实例化套接字对象
    			InetAddress address = InetAddress.getByName(server);//将服务器的ip地址封装成InetAddress的对象
    			packet_send = new DatagramPacket(data, data.length,address,port);//创建拥有服务器端口号服务器ip地址，还有要发送的信息的UDP数据包
    			socket.send(packet_send);//使用send()方法向服务器发送数据包
    			byte [] r = new byte [1024];//建立一个字节数为1024的缓冲流
    			packet_recive = new DatagramPacket(r, r.length);//设立接收包的对象
    			socket.receive(packet_recive);//使用receive()方法接收数据包
    			byte []response = packet_recive.getData();//得到接收包中的数据
    			int len = packet_recive.getLength();//得到接收包信息长度
    			String str1 = new String(response,0,len);//将接收包中的数据变成字符串
    			System.out.println(str1);//输出字符串
    		} catch (Exception e) {
        
    			System.out.println(e);
    		}finally {
        
    			socket.close();
    		}
    
    	}
    
    }

**运行结果：**  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NTE3NDIwOA_size_16_color_FFFFFF_t_70]![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NTE3NDIwOA_size_16_color_FFFFFF_t_70 1]![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NTE3NDIwOA_size_16_color_FFFFFF_t_70 2]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NTE3NDIwOA_size_16_color_FFFFFF_t_70]: https://img-blog.csdnimg.cn/20191204204505140.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NTE3NDIwOA==,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NTE3NDIwOA_size_16_color_FFFFFF_t_70 1]: https://img-blog.csdnimg.cn/20191204204513819.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NTE3NDIwOA==,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NTE3NDIwOA_size_16_color_FFFFFF_t_70 2]: https://img-blog.csdnimg.cn/20191204204521296.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NTE3NDIwOA==,size_16,color_FFFFFF,t_70